Nowadays, helmets for protection of cyclists and motorcyclist are more and more required to provide a safe transportation of the riders. Motorcyclists are required to wear a helmet when riding in many countries. The development of the motorcyclist helmets is thus very prosperous worldwide.
On the other hand, the cyclist helmet is not so emphasized due to the fact that the cyclists are usually moving in a much lower speed than the motorcyclists. This apparently influences the development of the cyclist helmets. Although the cyclists acknowledge the importance of wearing a helmet in protecting their lives, some cyclists do not like to wear the helmet because the conventional design of the cyclist helmet is an enclosing structure around the head of the cyclists so that air ventilation and thus heat dissipation is very difficult. It may be tolerable in winter time, but definitely in-tolerable in summer due to the sun radiation and the high temperature environment. It is an important issue to develop a helmet which the cyclists are willing to wear in both summer and winter to reduce life losses in traffic accidents.
U.S. Pat. No. 4,903,350 discloses a streamlined helmet which has a plurality of air inlets formed on the top surface of the helmet to allow air to enter the helmet interior so as to achieve the air ventilation and heat dissipation. Such a streamlined helmet, however, has no air conducting means formed inside the helmet interior to help expulsion of the air out of the helmet and this considerably influences the ventilation effect of the helmet.
It is therefore desirable to have an air ventilation helmet which comprises air conducting means therein to help exhaustion of interior air out of the helmet so as to overcome the deficiency of the conventional helmet.